1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to adaptive image size conversion, and more particularly, to adaptive image size conversion which adjusts an image size conversion rate according to features of image data to display the converted image on a screen.
2. Description of the Related Art
Generally, an image display device such as a television includes an image size conversion function such as 4:3 mode, 16:9 mode, panorama mode, enlargement 1 mode and enlargement 2 mode, and a user can adjust necessary modes to display the converted images on a screen.
FIG. 1 is a view illustrating a configuration of a conventional image size conversion apparatus.
Referring to FIG. 1, the conventional image size conversion apparatus includes a location detector 10, a scale ratio adjustor 12 and a scaler 14.
The location detector 10 detects information on a location of the present pixel in an input frame or field (Fn). The scale ratio adjustor 12 adjusts the scale ratio referring to the location information detected by the location detector 10. In detail, the scale ratio adjustor 12 adjusts the scale ratio to convert a size of the present pixel according to set modes. The scaler 14 changes the size of the frame or field (Fn) that is input according to the adjusted scale ratio.
FIG. 2 is a view illustrating an example of setting the scale ratio of a conventional image size conversion apparatus, and FIGS. 3A and 3B illustrate examples of image size conversion results of a conventional image size conversion apparatus.
The scale ratio of FIG. 2 is exemplified as a panorama. The panorama refers to a screen in which a central area A containing main characters or main scenes is not enlarged but only side areas B and C are enlarged, to naturally show an image generated by 4:3 ratio on a 16:9 screen. If an image is enlarged to a panorama size, a face area 22 or a letter area 24 included in the enlarged image is displayed on a screen 20 as distorted as shown FIGS. 3A and 3B.
Recently, lots of additional information is displayed on an image display device such as a television, using graphics or letters as well as an image. The graphics and letters may have an influence on readability if the scale ratio is not constant as the panorama of FIG. 2 when the image size is changed.
In detail, in case of letters transmitted through a ticker that moves at a constant speed and direction, the enlargement ratios between letters displayed on the central area A and the side areas B and C are different so that a user has a difficulty in reading letters.
Additionally, since human eyes can sensitively recognize a skin tone such as a face, the distortion is more significantly displayed in comparison with a general image if the face is displayed not on the central area A but on the side areas B and C. In case of graphics, since a luminance or a color is significantly changed, the distortion is more greatly displayed in comparison with a general image.